The overall purpose of the present study is the investigation of the relationships between brain proteins and lipids. The investigation is directed towards an understanding of the chemical architecture of the myelin sheath. Primary emphasis will be on the proteolipids with the long range goal of determining the amino acid sequence of the protein moiety. During the coming year the experimental approach will be directed towards a) the characterization of the multiple bands seen on SDS gel electrophoresis of proteolipids b) a study of conditions for the digestion of various types of proteolipid preparations by proteolytic enzymes, c) the isolation of pure peptides obtained from the enzymatic digestion and d) the determination of the amino acid sequence of the isolated peptides. An additional line of investigation will be undertaken on the immunological properties of the proteolipid apoprotein in collaboration with Dr. B. Arnason (Massachusetts General Hospital).